US Patent 7568456 Valve gear

There is provided a valve gear of an internal combustion engine converting a rotational motion of a motor into a linear motion by a cam, and driving an intake valve or an exhaust valve of a cylinder so as to be opened and closed based on the linear motion, a motor control apparatus which can actuate the motor in a rocking chive mode in which a rotating direction of the cam is changed during a lift of the valve. The motor control apparatus controls a motion of the motor such that the cam starts rotating before the valve starts lifting in the rocking drive mode.